Problem: If $a + b + c = 8$ and $x + y = 7$, what is $-8y - 2c - 2b - 8x - 2a$ ?
Solution: $= -2a - 2b - 2c - 8x - 8y$ $= (-2) \cdot (a + b + c) + (-8) \cdot (x + y)$ $= (-2) \cdot (8) + (-8) \cdot (7)$ $= -16 - 56$ $= -72$